As one of book binding processes, there is a cover attachment process of attaching a cover to a book block. In this process, a machine for attachment of a cover to a book block is used (see for example Patent Document 1). The machine includes a vertically movable press plate, and a pair of nip plates arranged on an upper surface of the press plate.
In the cover attachment process, the book block is held by a clamp unit above the pair of nip plates in such a manner that a lower end surface (a back surface) of the book block is opposed to a gap between the pair of nip plates and directed downward. The press plate is disposed at a lower standby position, and glue is applied to the lower end surface of the book block. When the press plate moves upward from the lower standby position to an upper press position, the cover is pressed against the lower end surface of the book block. While the press plate presses the cover against the lower surface of the book block, the nip plates nip both the book block and the cover in such a manner that the cover is pressed against both sides of a lower end portion of the book block, and the cover is attached to the book block.
In some conventional machines an operator can set a time (“a waiting time for nipping”) for which the press plate stays at the lower standby position, and a time (“a duration time for nipping”) for which the nip plates nip both the book block and the cover, so that the glue applied to the lower end surface of the book block can be dried to a predetermined cure degree. The lower end surface of the book block applied with the glue is held by the clamp unit, then the press plate moves upwardly from the lower standby position to the upper press position after the elapse of the waiting time for nipping. And the cover is pressed against the lower end surface of the book block. Thereafter, the nip plates nip both the book block and the cover, and move away from each other after the elapse of the duration time for nipping, so that the cover is attached to the book block.
In some conventional machines an operator can also set a time (a waiting time for producing a book without a cover) for which the glue dries. The machine generates an alarm signal in the form of sound and/or light to alarm to operators that the time has already passed.
The cover is pressed against the lower end surface of the book block by the press plate so as to attach the cover to the lower end surface of the book block with the glue, and the glue applied to the lower end surface of the book block is extruded to both sides of the lower end surface of the book block. Furthermore the cover is attached to the both sides of the lower end portion of the book block with side glue by the nip plates. As shown in FIG. 11A, the cover 12 is attached to both the lower end surface of the book block 4 and the both sides of the lower end portion thereof so that a book with beautiful appearance is produced.
However, depending on a viscosity of glue and/or a condition of an ambient temperature and so on, the conventional machine cannot sometimes produce the excellent finished book. As shown in FIG. 11B, due to a shortage of the side glue 40 of the both sides of the lower end portion of the book block 4, the cover 12 is attached only to the lower end surface of the book block 4, or as shown in FIG. 11C, the glue 40 is entered into the book block 4 so that there is a problem that a book with the cover 12 of poor appearance may be produced.
Patent Document 1: JP 2010-173070